In Japanese Patent Application Laid-Open (JP-A) No. 2005-206108, a configuration is described in which a rear end side of a left side floor frame and a rear end side of a right side floor frame (both referred to as “front side members” in JP-A No. 2005-206108) are coupled together through a brace having an X-shape in plan view (referred to as an “engine rear support member” in JP-A No. 2005-206108).
A configuration is also described in FIG. 3 of JP-A No. 2009-120100 in which a first transverse brace, connecting left and right floor frames (referred to in JP-A No. 2009-120100 as “floor members”), and a second transverse brace, provided at the rear of the first transverse brace and connecting both left and right sides of a floor tunnel, are connected together by first and second diagonal braces.